title: Halloysite nanotubule clay for efficient water purification.
abstract: Halloysite clay has chemical structure similar to kaolinite but it is rolled in tubes with diameter of 50 nm and length of ca. 1000 nm. Halloysite exhibits higher adsorption capacity for both cationic and anionic dyes because it has negative SiO2 outermost and positive Al2O3 inner lumen surface; therefore, these clay nanotubes have efficient bivalent adsorbancy. An adsorption study using cationic Rhodamine 6G and anionic Chrome azurol S has shown approximately two times better dye removal for halloysite as compared to kaolin. Halloysite filters have been effectively regenerated up to 50 times by burning the adsorbed dyes. Overall removal efficiency of anionic Chrome azurol S exceeded 99.9% for 5th regeneration cycle of halloysite. Chrome azurol S adsorption capacity decreases with the increase of ionic strength, temperature and pH. For cationic Rhodamine 6G, higher ionic strength, temperature and initial solution concentration were favorable to enhanced adsorption with optimal pH 8. The equilibrium adsorption data were described by Langmuir and Freundlich isotherms.
authors.affiliation: Institute for Micromanufacturing, Louisiana Tech University, Ruston, LA 71272, United States.
authors.forename: Yafei
authors.initials: Y
authors.lastname: Zhao
authors.forename: Elshad
authors.initials: E
authors.lastname: Abdullayev
authors.forename: Alexandre
authors.initials: A
authors.lastname: Vasiliev
authors.forename: Yuri
authors.initials: Y
authors.lastname: Lvov
mesh_terms: D000327:Adsorption; D000538:Aluminum Silicates / Q000737:chemistry*; D000077215:Clay; D017743:Equipment Reuse; D005374:Filtration / Q000295:instrumentation; D006863:Hydrogen-Ion Concentration; D062385:Hydroxybenzoates / Q000302:isolation & purification; D007616:Kaolin; D043942:Nanotubes; D009994:Osmolar Concentration; D012235:Rhodamines / Q000302:isolation & purification; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods*
chemical_list: D000538:Aluminum Silicates; D062385:Hydroxybenzoates; D012235:Rhodamines; D014874:Water Pollutants, Chemical; C026188:rhodamine 6G; C015076:chrome azurol S; D007616:Kaolin; D000077215:Clay
keywords: Adsorption; Chrome azurol; Clay; Filtration; Halloysite nanotubes; Kaolinite; Rhodamine